US4499859A - Vapor generator - Google Patents

Vapor generator Download PDF

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Publication number
US4499859A
US4499859A US06/495,584 US49558483A US4499859A US 4499859 A US4499859 A US 4499859A US 49558483 A US49558483 A US 49558483A US 4499859 A US4499859 A US 4499859A
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United States
Prior art keywords
row
tubes
solution
solution tubes
inner casing
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Expired - Fee Related
Application number
US06/495,584
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English (en)
Inventor
Akira Nishiguchi
Sanpei Usui
Tomihisa Oouchi
Kazumi Iwai
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Hitachi Ltd
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Hitachi Ltd
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Assigned to HITACHI, LTD., 5-1, MARUNOUCHI 1-CHOME, CHIYODA-KU, TOKYO, JAPAN, A CORP. OF JAPAN reassignment HITACHI, LTD., 5-1, MARUNOUCHI 1-CHOME, CHIYODA-KU, TOKYO, JAPAN, A CORP. OF JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: IWAI, KAZUMI, MACHIZAWA, KENZI, NISHIGUCHI, AKIRA, OOUCI, TOMIHISA, USUI, SANPEI
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B33/00—Boilers; Analysers; Rectifiers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B7/00—Steam boilers of furnace-tube type, i.e. the combustion of fuel being performed inside one or more furnace tubes built-in in the boiler body
    • F22B7/04—Steam boilers of furnace-tube type, i.e. the combustion of fuel being performed inside one or more furnace tubes built-in in the boiler body with auxiliary water tubes
    • F22B7/06—Steam boilers of furnace-tube type, i.e. the combustion of fuel being performed inside one or more furnace tubes built-in in the boiler body with auxiliary water tubes inside the furnace tube in transverse arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2333/00—Details of boilers; Analysers; Rectifiers
    • F25B2333/003—Details of boilers; Analysers; Rectifiers the generator or boiler is heated by combustion gas

Definitions

  • the present invention relates to a vapor generator and, more particularly, to a vapor generator for use in a cooler or heater of absorption type or to a steam generator which generates steam for air conditioning purpose.
  • a plurality of vertically extending tubes are arranged in rows such that tubes of one row are staggered from those of adjacent rows when viewed in plan.
  • each tube of second row appears through the gap between each pair of adjacent tubes of first row, when viewed in the direction of flow of the gas.
  • One problem of such an arrangement of the tubes resides in the fact that the tubes of the first row restrict the area of passage for the gas. As a result, the flow velocity of the gas is through the restricted passages formed between respective two adjacent tubes of the first row is increased, and the gas of increased velocity is directed to the center of each tube of the second row due to a nozzle action performed by each restricted flow passage.
  • an object of the invention is to provide a vapor generator improved to eliminate local heating of tubes.
  • Another object of the invention is to prolong the life of vapor generator by eliminating local overheat.
  • Still another object of the invention is to provide a vapor generator having a reduced size.
  • the walls defining the flue is provided at portions thereof around the flame with fins so that the heat is delivered at a greater rate to the medium in the drum around the flue than in the conventional vapor generator through the fins and the walls defining the flue. Consequently, the temperature of the gas entering the region of the first row of the tubes is lowered to such a level so as to eliminate local overheating of the tubes.
  • the axis of each tube in the second row is disposed at a deviation in the direction perpendicular to the direction of flow of the gas from the gap between two adjacent tubes in the first row. More specifically, an offset a of the axes of tubes in the second row from the center axis of the gap between two adjacent tubes in the first row is determined to satisfy the condition of S/2 ⁇ a ⁇ (D-S)/2, where, D represents the outside diameter of the tubes in the second row and S represents the space between two adjacent tubes in the first row, on condition that the relationship expressed by D>2S is met.
  • the tubes of the first row have an outside diameter greater than the diameter or diameters of the tubes in the second and subsequent rows of tubes, so as to suppress the tendency of local superheating of tubes in the first row.
  • the rate of heat transfer from the gas to the tube is in inverse proportion to the root of the radius of curvature of the foremost end of the tube.
  • the greater outside diameter, i.e. the greater radius of curvature of the tube surface reduces the rate of heat transfer from the gas to the tubes in the first row so that the temperature of the tubes in the first row is effectively lowered even when the gas temperature is high. This effectively contributes to the elimination of overheating of the tubes in the first row.
  • FIG. 1 is a plan view of a typical embodiment of a constructed in accordance with the invention
  • FIG. 2 is a cross sectional view taken along the line II-II in FIG. 1;
  • FIG. 3 is a cross sectional view taken along the line III-III in FIG. 1;
  • FIG. 4 is a cross sectional view taken along the line IV-IV in FIG. 1;
  • FIG. 5 is a plan view of a burner.
  • a generator incorporated in an absorption type heater includes a burner section generally designated by the reference numeral 1 including burners comprising a premixing chamber 11 in which a gasified liquid fuel or a gaseous fuel is premixed with primary air; linear ports 12; linear flame ports 13; passages 14 for introducing secondary air to the area around the flame ports 13; a restriction 15a for defining a restricted linear passage 15 opposing to the flame ports 13; primary combustion chamber 16; a scondary combustion chamber 18 having nozzle ports 17 for jetting tertiary air to the area downstream from the restriction 15 from both sides of the flame; a tertiary air chamber 19 and so forth.
  • the generator also includes a boiler section generally designed by the reference number 2 having a rectangular parallelepiped outer casing 21, an inner casing 22 which also has a parallelepiped rectangular form, a plurality of solution pipes 23 attached to the inner casing 22, a large number of fins 24 attached to the inner casing 22, passage adjusting plates 25 for preventing bypassing of the gas and maintaining a substantially constant area of flow passage, solution supply pipe 26, baffle plate 27 for separating liquid fraction of droplets from the vapor and a partition wall 28.
  • a boiler section generally designed by the reference number 2 having a rectangular parallelepiped outer casing 21, an inner casing 22 which also has a parallelepiped rectangular form, a plurality of solution pipes 23 attached to the inner casing 22, a large number of fins 24 attached to the inner casing 22, passage adjusting plates 25 for preventing bypassing of the gas and maintaining a substantially constant area of flow passage, solution supply pipe 26, baffle plate 27 for separating liquid fraction of droplets from the vapor and a partition wall 28.
  • the outer casing 21 has an end plate 21A thicker than other walls of the outer casing 21, namely, two side walls 21B and 21C, welded to the end plate 21A, a bottom wall 21D, a top wall 21E and a second end wall 21F, welded to the ends of the side walls 21B, 21C, bottom wall 21D and the top wall 21E.
  • Both side walls 21B and 21C and the bottom wall 21D are formed integrally by bending a flat sheet material into a substantially U-shaped configuration, although these walls may be formed separately and welded together.
  • the inner casing 22 is composed of two side walls 22A and 22B, a top wall 22C and a bottom wall 22D which are welded together into the rectangular parallelepiped form.
  • the inner casing 22 is welded at its one end to the end plate 21A of the outer casing 21 and at its other end to the second end plate 21F of the outer casing 21, so that a space 29 for accomodating a medium to be heated and a space 30 for separating vapor from liquid droplets are formed between the outer casing 21 and the inner casing 22.
  • the partition wall 28 has a U-shaped horizontal section and is welded at both ends of legs of the U-shape to the end plate 21A while the upper and lower ends are welded to the top wall 22C and bottom wall 22D.
  • a plurality of fins 24 are secured to both side walls 22A, 22B of the inner casing 22, as well as to the partition wall 28.
  • the height of the fins 24 from the wall surface is gradually increased towards a longitudinal mid portion but is held constant in the region beyond the longitudinal mid portion.
  • Three solution pipes 23 are connected at their upper and lower end to the top wall 22C and bottom wall 22D of the inner casing 22.
  • the interior of the solution pipes 23 are communicated with the space 29.
  • the solution tubes 23A of the first row have an outside diameter D which is greater than the diameter or diameters of the tubes in the second and following rows.
  • the solution tubes 23B in the second and third rows have an outside diameter smaller than that D of the solution tubes 23A in the first row.
  • the axis of each solution tube 23B in the second row is offset from the gap between two adjacent solution tubes 23B in the second row.
  • the positions of the solution tubes 23B in the second row are determined to meet the condition of: S/2 ⁇ a ⁇ (D-S)/2, where, D represents the outside diameter of the solution tubes 23A in the first row, S represents the distance or gap between two adjacent solution tubes 23A in the first row and a represents the distance between the center axis of the gap between two adjacent solution tubes 23A in the first row and the axis of the solution tube 23B in the second row.
  • the solution tubes 23B in the third row are arranged such that the axis of each of these tubes laps the gap between two adjacent solution tubes 23B in the second row. In other words, the solution tubes in the second and third rows are arranged in a staggered manner.
  • Solution tubes 23C in the fourth to eighth rows are arranged in a staggered form. Although in the illustrated embodiment the finned solution tubes 23C are arranged in five rows, any suitable number of such rows not less than three is selected in accordance with the capacity of the boiler, i.e. the desired rate of evaporation, or the total heat transfer rate.
  • the flow passage adjusting plates 25 are attached to the inner surfaces of both side walls 22A and 22B of the inner casing 22 to extend vertically therealong, in alignment with the solution tubes 23B, 23C in the third, fifth and seventh rows.
  • the flow passage adjusting plates 25 are disposed at such positions where the distance or gap between the inner surfaces of side walls 22A, 22B and the outermost solution tubes 22B, 22C is large, so as to prevent by-passing of the gas through the gap between the solution tubes 23B, 23C and the inner surfaces of the side walls 22A, 22B of the inner casing 22.
  • the medium supply pipe 26 for supplying the medium to be heated has an opening positioned substantially at lengthwise mid point in the space 29. In the illustrated embodiment, the medium to be heated is supplied from an absorber into the space 29 through the supply pipe 26.
  • a medium outlet 31 and a vapor outlet 32 are respectively formed in the side wall 21B and the top wall 21E of the outer casing 21.
  • the outlet 31 is connected to the absorber, while the outlet 32 is connected to the condenser, respectively.
  • the absorption type water cooler or heater reference is made to the specification of U.S. Pat. No. 3,287,928 and Japanese Pat. No. 647,515.
  • the burner section 1 is fixed to the end plate 21A of the outer casing 21, to which is secured a heat shielding plate 34 projecting into the secondary combustion chamber 18 of the burner section 1.
  • the heat shielding plate 34 a provided, at its portion thereof confronting the tertiary air outlet 17, with a tertiary air passage 34A.
  • the heat shielding plate 34 may be integral with the end plate 21A or may be separate therefrom.
  • the to burners in the burner section 1 are started so as to form flame within the combustion chamber 33 of the inner casing 22.
  • the flame and the resultant combustion gas flow through the inner casing 22 while delivering heat to the medium to be heated through the fins 24, walls 22A, 22B, 22C and 22D of the inner casing 22 and the solution tubes 23 to thereby generate vapor of the solution.
  • Any liquid phase or droplets in the vapor is separated from the vapor as the latter comes into contact with the baffle plate 27 as it flows across the space 30, and the vapor, having almost no liquid phase, is forwarded to the condenser.
  • the medium rich in liquid phase is introduced through the supply pipe 26 into the space 29 where the liquid phase is evaporated to become vapor by the heat given by the gas.
  • the medium, now having only small liquid content, is introduced to the absorber through the outlet 31.
  • the local overheating of the solution tubes 23A and 23B in the first and second rows is avoided for the following reasons.
  • the height of the fins 24 is so selected in view of the shape of the flame formed by the burner section 1 that the fins 24 are not directly contacted by the flame. It is, therefore, possible to effectively transfer the heat from the gas of high temperature around the flame to the medium around the combustion chamber 33 through the fins 24, walls 22A, 22B, 22C and 22D of the inner casing 22 and the partition wall 28 by, for example, convection, while avoiding substantial overheating of the fins 24 and suppressing the generation of CO.
  • the rate of heat transfer i.e. the heat flux
  • the temperature of the combustion gas is lowered to such a level so as not to cause any excessive increase of heat flux applied to the solution tubes 23A even when the distance between the solution tubes 23A and the flame is decreased. It is, therefore, possible to reduce the length of the combustion chamber 33.
  • the rate of local heat transfer to the foremost end of the first row is decreased in inverse proportion to the root of the increased radius of curvature of the tube surface.
  • the aluminum wall 18a of the secondary combustion chamber is heated to a high temperature (about 350° C.) which can not be withstood by aluminum due to the transfer of heat by radiation or convection from the combustion gas of high temperature (1300° to 1500° C.) under reaction within the secondary combustion chamber.
  • the excessive heating of the wall 18a of the secondary combustion chamber imposes also a problem of fatigue rupture in the joint between the wall 18 and the end plate of the boiler section due to thermal stress caused by the difference in the thermal expansion coefficient.
  • a vapor generator was actually constructed in accordance with the invention.
  • the vapor generator had a capacity of 20 ref. tons with two burners each having a heat output of 30000 Kcal/h. It was confirmed that the volume of the vapor generator as a whole can be reduced remarkably, in fact almost to a half, as compared with the conventional vapor generator having the same capacity.
  • an easy capacity control was achieved due to the use of two burners. Additionally, the burners where effectively cooled by the combustion air in the combustion air chamber surrounding the burners.
  • aluminum linear burner having a small size and high heat output is used to permit a reduction of size of the combustion chamber. Additionally, undesirable local overheating of the foremost ends of the solution tubes is avoided by the provision of fins on the walls of the combustion chamber and by the offset of the solution tubes in the second row from the center of the gap of two adjacent solution tubes in the first row. Consequently, according to the invention, it is possible to attain a uniform heating of the whole vapor generator and, hence, to increase the mean heat flux, to thereby reduce the size and cost of the generator.
  • the reduced length of the flue afforded by the provision of fins to the combustion chamber wall, permits a reduction in the amount of medium to be heated held in the vapor generator, which, in turn, makes it possible to reduce the size of the generator and to shorten the time required until the generation of vapor to thereby considerably improve the start-up characteristics of the absorption type water cooler or heater.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Detergent Compositions (AREA)
US06/495,584 1982-05-21 1983-05-18 Vapor generator Expired - Fee Related US4499859A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP57084740A JPS58203371A (ja) 1982-05-21 1982-05-21 蒸気発生装置
JP57/84740 1982-05-21

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US4499859A true US4499859A (en) 1985-02-19

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5199384A (en) * 1988-12-22 1993-04-06 Miura Co., Ltd. Quadrangular type multi-tube once-through boiler
US5273001A (en) * 1988-12-22 1993-12-28 Toshihiro Kayahara Quadrangular type multi-tube once-through boiler
US5347957A (en) * 1991-07-26 1994-09-20 Tokyo Gas Company Ltd. Water heater with reduced NOx output
US5353748A (en) * 1992-09-09 1994-10-11 Miura Co., Ltd. Combustion method and apparatus for reducing emission concentrations of NOx and CO
US5435154A (en) * 1993-01-26 1995-07-25 Hitachi, Ltd. High temperature regenerator of an absorption type hot and cold water generator and absorption type hot and cold water generator
US5558046A (en) * 1992-03-05 1996-09-24 Dr.-Ing. Fritz Schoppe Fire-tube boiler
US5713310A (en) * 1996-04-22 1998-02-03 Clarke Industries, Inc. Heat exchanger for pressure washer
WO2000068622A1 (en) * 1999-05-11 2000-11-16 Lattice Intellectual Property Ltd. An absorption chiller
EP1154206A2 (en) * 2000-05-10 2001-11-14 Eaton-Williams Group Limited A gas-fired humidifier
US6470702B2 (en) * 1997-11-12 2002-10-29 Hitachi, Ltd. Absorption water heater/chiller and high temperature regenerator therefor
EP1286121A3 (en) * 2001-08-09 2004-09-08 Ebara Corporation Absorption chiller-heater and generator for use in such absorption chiller-heater
US20070186565A1 (en) * 2004-06-15 2007-08-16 Ned Baudat Apparatus and methods for converting cryogenic fluid into gas
US20090173292A1 (en) * 2008-01-04 2009-07-09 Christie David M Steam boiler
CN108167845A (zh) * 2017-12-05 2018-06-15 广州市万屋净环保科技有限公司 一种室内污染物燃烧分解装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159571A (en) * 1935-08-13 1939-05-23 Elmer S Stack Water heater
US3934554A (en) * 1974-06-03 1976-01-27 Carlson Philip E Water and room heater
US4344386A (en) * 1971-10-26 1982-08-17 Black Robert B Heat transfer equipment and method
US4356794A (en) * 1979-10-25 1982-11-02 Tricentrol Benelux B.V. Hot water boiler

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159571A (en) * 1935-08-13 1939-05-23 Elmer S Stack Water heater
US4344386A (en) * 1971-10-26 1982-08-17 Black Robert B Heat transfer equipment and method
US3934554A (en) * 1974-06-03 1976-01-27 Carlson Philip E Water and room heater
US4356794A (en) * 1979-10-25 1982-11-02 Tricentrol Benelux B.V. Hot water boiler

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5273001A (en) * 1988-12-22 1993-12-28 Toshihiro Kayahara Quadrangular type multi-tube once-through boiler
US5199384A (en) * 1988-12-22 1993-04-06 Miura Co., Ltd. Quadrangular type multi-tube once-through boiler
US5347957A (en) * 1991-07-26 1994-09-20 Tokyo Gas Company Ltd. Water heater with reduced NOx output
US5558046A (en) * 1992-03-05 1996-09-24 Dr.-Ing. Fritz Schoppe Fire-tube boiler
US5353748A (en) * 1992-09-09 1994-10-11 Miura Co., Ltd. Combustion method and apparatus for reducing emission concentrations of NOx and CO
CN1037290C (zh) * 1992-09-09 1998-02-04 三浦工业株式会社 降低氧化氮和一氧化碳排放浓度的燃烧方法和设备
US5435154A (en) * 1993-01-26 1995-07-25 Hitachi, Ltd. High temperature regenerator of an absorption type hot and cold water generator and absorption type hot and cold water generator
US5713310A (en) * 1996-04-22 1998-02-03 Clarke Industries, Inc. Heat exchanger for pressure washer
US6470702B2 (en) * 1997-11-12 2002-10-29 Hitachi, Ltd. Absorption water heater/chiller and high temperature regenerator therefor
WO2000068622A1 (en) * 1999-05-11 2000-11-16 Lattice Intellectual Property Ltd. An absorption chiller
EP1154206A3 (en) * 2000-05-10 2002-07-10 Eaton-Williams Group Limited A gas-fired humidifier
EP1154206A2 (en) * 2000-05-10 2001-11-14 Eaton-Williams Group Limited A gas-fired humidifier
EP1286121A3 (en) * 2001-08-09 2004-09-08 Ebara Corporation Absorption chiller-heater and generator for use in such absorption chiller-heater
US20070186565A1 (en) * 2004-06-15 2007-08-16 Ned Baudat Apparatus and methods for converting cryogenic fluid into gas
US20090173292A1 (en) * 2008-01-04 2009-07-09 Christie David M Steam boiler
US7823544B2 (en) 2008-01-04 2010-11-02 Ecr International, Inc. Steam boiler
CN108167845A (zh) * 2017-12-05 2018-06-15 广州市万屋净环保科技有限公司 一种室内污染物燃烧分解装置
CN108167845B (zh) * 2017-12-05 2021-02-12 广州市万屋净环保科技有限公司 一种室内污染物燃烧分解装置

Also Published As

Publication number Publication date
JPS634113B2 (ja) 1988-01-27
JPS58203371A (ja) 1983-11-26

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